Basically, I'm piecing together a build for a friend of mine and we got to talking about solid rollers and high RPM LSx builds.

The idea was take my ls7 (stock) and balance a build that will yield anywhere from 650rwhp-680rwhp N/A 11.5:1 (or close to that) PUMP GAS, turning under 8k RPM's and without turning it into a dedicated track car or having to check for lash/replace springs a few times a year. The goal is to turn the rpm range up another 1000rpm solid, shifts in the 7600-7900 range with really killing the mid-range (3500-5000) or make it a top heavy build. The idea is not run a 290/303 @ .050 .800 type of cam either. I would like to have the springs last at least a year or driving! However, lifts in the high 600's, maybe a .750 with durations in the 250's+ (speced for the LS7= big split) would be acceptable if it doesn't idle like a pro mod!

My understanding that the solid roller stuff has gotten much more reliable and less finicky, but I would like to ask the expert (yeah, that's you!) on what would be the limit, the fine line if you will, between a solid roller that is comfortable to DD with and what is a track car setup.

To start, a C6 Z06 making about 600-610rwhp is already going to have a decent cam in it. I'm not asking for "if it surges" types of answers, I'm mainly considering the valvetrain and the maintenance behind the solid stuff.

So, going from there, I know that certain parts will be needed to make the best of the combo. A sheetmetal intake or a ITB if you can fit and tune it right. A solid roller cam, All-Pro heads in the 400-420cfm+ range, the solid valvetrain to make it all work together, titanium valves, maybe some aluminum rods, maybe... and well prepped LS7 block, forged crank, girdle, etc.

From there...

1. When it comes to solid roller, would it be a better DD by going with a solid/hydraulic valvetrain setup or a solid/solid for a build like this?

2. Being as brutally honest as possible, how reliable can the valvetrain be without sacrificing longetivity? No 3K mile lash checks, new springs every 3k miles, etc.

3. Would it be best to run a BBC lifter for a more reliable lifter? Again, what about the hydraulic lifter with a solid cam spec?

4. What about the TB? Can a 102mm NW handle that kind of airflow or would I need to move with something more serious?

5. Ignition signal, is the factory juice boxes enough of would I need to run something with a more stable spark deployment at high rpms?


... lots of questions, I know. I'm just trying to pick some of the best brains on here. Ya'll know of a sticky/thread that might have some of these answers?

So, to recap, we wanted to take the already potent LS7 H/C packages that are available now, which are regularly making 590-610rwhp (with a FAST 102mm) and build up from there. Of course the money invested at that level is steep and at times a simple nitrous hit would be much simpler to piece together but no nitrous here.... well, not yet.

A combo like this should be around 780-800hp crank with realistically no more than 8k rpms, maybe 8200 we can find a way to trick the stock PCM to "see" past 8k. But for the time being, 8k rpms will be fine.

So?!

 

This is a serious inquiry y'all .. not just wasting anyone's time.

I'm trying to learn the real world limitations of running a solid in "street" trim.

 

I'm interested as well. I've been throwing the idea around in my head for quite a while. I don't mind the maintenance as much (setting lash) but don't want to be replacing springs every 20 passes or 3000 miles ether.

 

My thoughts exactly. I've heard/read that the maintenance (lash, spring life) has gotten better once a year versus 3-4 times a year. I just want to get all the facts straight better jumping in to this project.

 

Here is my opinion. Take it for what it worth. I may be wrong, but anyway.

If you are wanting to run that many RPM, you are leaving a ton of power on the table by sticking with that CR, and therefore the pump gas.

IMHO, I don't think you can get to the power figures you want on pump gas out of a 427, no matter if you run a solid roller or hydraulic.

Like I said, that is just MHO.

 

I appreciate the honesty.

But, If H/C c6 Z06 LS7's are already in the 590-630rwhp N/A (Livernois, LPE GT-21, RR Punisher H/C, Vette-doctors, RPM "fran") ON PUMP GAS then it would seem logical to assume that with a cam that will be able use up the air flow from a head that flows great in the .700+ range and an intake to supply the heads the necessary air... Long winded, I know!

... then by stretching the powerband another 1k rpms and using a more aggressive cam profile and better flowing/more stable top-end, I don't where I/we couldn't get another 50-80rwhp AT LEAST using pump.

Or is there a power limitation with pump gas that I don't know about? I know that in a N/A package such as this a high CR with C16, for example, would make the power easier but this is for a streetcar and one of the stipulations is to make it without the use of race fuel.

I think 700rwhp N/A on 93oct. is possible with the right sum of parts but the trick is to find a cam profile that is street friendly (not 600rpm idle no surge pussycat) without having to replace springs 2-3 times a year and checking lash ever oil change.

 

Sounds to me like you need to look into some short travel hydraulic lifters. Erik @ HKE has been working on some stuff for 7500-8000 rpm hydraulic setups.

 

Hmmm... thanks. You don't happen to know the cost of those lifters? Also, I'm assuming that these lifters are designed or can be run with a solid cam profile.